1. Field of the Invention
The present invention relates to an image processing apparatus and a method of controlling the image processing apparatus.
2. Description of the Related Art
A technology to express high dynamic range (HDR) video is disclosed in Japanese Patent Application Laid-Open No. 2003-046857 , for example. In concrete terms, Japanese Patent Application Laid-Open No. 2003-046857 discloses a technology for generating one frame of an HDR video from one frame of an original image by alternately using two different algorithms.
On the other hand, a dynamic range can be apparently improved by generating an image (low brightness image) in which gradation of an image in a high brightness area is enhanced and an image (high brightness image) in which gradation of an image in a low brightness area is enhanced, from the imput image, and alternately displaying these two images. Such a video of which dynamic range is improved is called an “HDR video” hereinbelow. However if an HDR video is generated from the input video by this method, an apparent frame rate remains as the frame rate of the input video, even if the frame rate of the HDR video is double that of the frame rate of the input video, as shown in FIG. 11. If an HDR video is generated by the above mentioned method after converting the frame rate on the input video (generating interpolated frame images), the frame rate of the HDR video becomes high, as shown in FIG. 12. In concrete terms, the frame rate of the HDR video becomes double that of the frame rate of the input video for which frame rate was converted. Therefore the frame rate of the HDR video may exceed the frame rate of a video that can be displayed on a display.